Stitch regulator for a sewing machine

ABSTRACT

A stitch regulator ( 50 ) for use with a sewing machine ( 34 ) transported by a moveable platform ( 26 ) includes a housing ( 52 ) configured to be coupled to one of the sewing machine ( 34 ) and the moveable platform ( 26 ). An X-axis rate sensor ( 92 ) and a Y-axis rate sensor ( 96 ) determine movement of the sewing machine ( 34 ) on the moveable platform ( 26 ). A microcontroller ( 118 ) is contained in the housing ( 52 ) and is in communication with the sensors ( 92, 96 ). The microcontroller ( 118 ) generates a motor control signal ( 126 ) in response to the movement of the sewing machine ( 34 ) for input into a motor control input port ( 88 ) of the sewing machine ( 34 ).

RELATED INVENTION

The present invention claims priority under 35 U.S.C. §119(e) to: “SpeedControl for a Sewing Machine,” U.S. Provisional Patent Application Ser.No. 60/632,563, filed 1 Dec. 2004, which is incorporated by referenceherein.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to the field of sewing machines. Morespecifically, the present invention relates to a stitch regulator foruse with a sewing machine transported by a moveable platform relative toa piece of fabric.

BACKGROUND OF THE INVENTION

Quilting has been in practice for many years, initially for utilitarianpurposes, and more recently as a way of artistic expression. Thecontinued popularity of the craft has lead to the development of moderntextiles, equipment, and labor-saving sewing devices.

Quilting typically entails sewing two layers of cloth with a layer ofinsulating batting in between, thus forming a quilt. Quilts may beformed in a variety of shapes and styles that are variously used tocover beds, to decorate walls, used as lap cloths, and so forth. Designsand patterns are typically sewn, or stitched, into a quilt by hand orwith a sewing machine to secure the two layers of cloth and the layer ofbatting together. Complex designs and patterns are often hand-stitchedby a skilled craftsperson. However, such hand-stitching can be too timeconsuming for a skilled craftsperson, and may be too challenging forthose who are not as skilled at hand-stitching. In addition,hand-stitching may be difficult or even impossible for those withlimited mobility of their fingers, such as for an individual who hasarthritis. Thus, some individuals utilize machine sewing techniques tostitch a quilt.

Unfortunately, however, when using a sewing machine, the hobbyist mustmanipulate an unwieldy, multilayered fabric sandwich under the needlebar of the sewing machine. Such manipulation can be difficult, and causepuckering and stitching errors. Accordingly, market demand has lead tothe development of quilting devices for holding the fabric to be quiltedand moving the sewing machine relative to the fabric. A quilting tableis one such quilting device.

FIG. 1 shows a front perspective view of a prior art quilting table 20.Quilting table 20 generally includes a frame 22, a fabric support system24 for holding the fabric to be quilted, a platform assembly 26, and anoverhead shelf 28. Platform assembly 26 is moveable relative to alongitudinal dimension, or X-axis 30, and a transverse dimension, orY-axis 32, of frame 22. In general, platform assembly 26 supports andtransports a conventional, household sewing machine 34, for movingsewing machine 34 relative to the fabric.

Frame 22 generally holds one or more payout rollers 36, onto whichfabric is rolled, and a take-up roller 38. Take-up roller 38 istypically directed through the throat of sewing machine 34 so thatfabric suspended between payout rollers 36 and take-up roller 38 can bepassed under the needle bar of sewing machine 34 for machine stitching.Platform assembly 26 typically includes two carriages, one sitting uponthe other. One carriage moves in the longitudinal direction, i.e., alongX-axis 30, and the other carriage moves upon the first carriage in thetransverse direction, i.e., along Y-axis 32. Platform assembly 26 canthen be manually manipulated by the user to impart a stitch pattern ontothe fabric.

A handle 40 may be coupled to platform assembly 26 on a needle side 42of quilting table 20 for manually translating the carriages of platformassembly 26 longitudinally and transversely relative to X-axis 30 andY-axis 32. In such a configuration, an individual may be located at andoperate sewing machine 34 from needle side 42 of quilting table 20. Assuch, the fabric and needle of sewing machine 34 are readily visible tothe individual as the fabric is being stitched. In order to facilitateoperation of sewing machine 34 from needle side 42 of quilting table 20,handle 40 may include the capability to both turn off and turn on sewingmachine 34. In addition, handle 40 may include the capability to adjustan operational speed of sewing machine 34.

Stitch regulators that provide the capability to both turn off and turnon, as well as to adjust the operational speed of, a sewing machine areknown for utilization with a quilting table. One prior art stitchregulator includes a computer board located inside of the sewing machineand having a controller mounted thereon. The prior art stitch regulatorfurther includes front and rear control panels and handle switches, twotrack sensors, and a needle position sensor. The stitch regulator isdriven by software embedded inside a microchip. The track sensorsmeasure the changing location of the needle as the sewing machine ismoved on the platform assembly, and the needle position sensorrecognizes if the needle is up or down. The stitching mode and othercommands are set on the control panel. The controller uses the needlelocation data, the needle up/down data, and the entered stitching modeand other commands to determine when a stitch should be completed andsends a motor control signal to the sewing machine motor.

While such a stitch regulator can be useful for an operator, prior artstitch regulators suffer from a number of problems. For example, thestitch regulator discussed above requires installation of a portion ofthe device inside of the sewing machine. Therefore, it cannot be readilyimplemented with a number of sewing machines without invasive and costlymodification to the sewing machines.

A further problem with prior art stitch regulators is that currentstitch regulator systems are not necessarily accurate regarding stitchregulation across a variety of machine types. This inaccuracy occursbecause the actual motor speed of a particular motor is affected by thecharacteristics of that motor. Consequently, a motor control signalinput to a motor of one type of sewing machine might not cause the motorto operate at the same speed as when the motor control signal is inputto a motor of a different type of machine. Therefore, stitch regulationcould be inconsistent across a variety of machine types.

Another deficiency in the current stitch regulator systems is that themotor speed for each type of machine is not necessarily linear with themotor control signal. That is, sending a motor control signal that istwice the motor speed of a first motor control signal does notnecessarily make the sewing machine motor run twice as fast as the firstmotor control signal. This situation can further lead to inconsistentstitch regulation at various operational speeds of a sewing machine.

SUMMARY OF THE INVENTION

Accordingly, it is an advantage of the present invention that a stitchregulator for use with sewing machine transported by a moveable platformis provided.

It is another advantage of the present invention that a stitch regulatoris provided that yields consistent stitch regulation across a variety ofsewing machine types.

Another advantage of the present invention is that a stitch regulator isprovided that yields consistent stitch regulation across a wide varietyof motor speeds for a sewing machine.

Yet another advantage of the present invention is that a stitchregulator is provided that is intuitive to utilize, is located exteriorto a sewing machine, and is cost effectively manufactured.

The above and other advantages of the present invention are carried outin one form by a stitch regulator for use with a sewing machinetransported by a moveable platform, the sewing machine having a motorcontrol input port. The stitch regulator includes a housing configuredto be coupled to one of the sewing machine and the moveable platform,and a sensor adapted for communication with the sewing machine fordetermining movement of the sewing machine on the moveable platform. Amicrocontroller is contained in the housing and is in communication withthe sensor. The microcontroller generates a motor control signal inresponse to the movement of the sewing machine, for input into the motorcontrol input port.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention may be derived byreferring to the detailed description and claims when considered inconnection with the Figures, wherein like reference numbers refer tosimilar items throughout the Figures, and:

FIG. 1 shows a front perspective view of a prior art quilting table;

FIG. 2 shows a front perspective view of a stitch regulator inaccordance with a preferred embodiment of the present invention;

FIG. 3 shows an exploded side view of a housing of the stitch regulator;

FIG. 4 shows an exploded perspective view of a platform assembly with astitch regulator mountable thereon;

FIG. 5 shows a partial front view of the stitch regulator illustratingkeypad controls;

FIG. 6 shows a block diagram of the stitch regulator;

FIG. 7 shows a block diagram of a portion of the stitch regulator;

FIG. 8 shows a graph typifying a motor characteristic for a sewingmachine;

FIG. 9 shows a flow chart of a stitch regulator operation process; and

FIG. 10 shows a table of formulas executed within the stitch regulatorfor determining a motor control signal for input into a sewing machine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides a stitch regulator for use with a sewingmachine. Such a stitch regulator may be utilized for controlling motorspeed of a sewing machine mounted on a moveable platform assembly, suchas that utilized on quilting table 20 (FIG. 1).

Referring to FIGS. 2-4, FIG. 2 shows a front perspective view of astitch regulator 50 in accordance with a preferred embodiment of thepresent invention. FIG. 3 shows an exploded side view of a housing 52 ofstitch regulator 50 (FIG. 2), and FIG. 4 shows an exploded perspectiveview of a platform assembly, such as platform assembly 26, with stitchregulator 50 mountable thereon. For clarity of the following discussion,stitch regulator 50 is utilized in connection with platform assembly 26and sewing machine 34 (FIG. 1). However, it will become readily apparentthat stitch regulator 50 is not limited for use with the particularplatform assembly 26 and sewing machine 34 discussed herein, but mayinstead be adapted for use with a number of moveable platforms andsewing machine types.

Stitch regulator 50 includes housing 52 configured to be coupled toeither of sewing machine 34 or platform assembly 26. In this exemplaryconfiguration, stitch regulator 50 may couple, or bolt, to platformassembly 26. As mentioned above, platform assembly 26 supports andtransports sewing machine 34 (FIG. 1) relative to X-axis 30 and Y-axis32. Platform assembly 26 generally includes a first carriage 54 and asecond carriage 56.

First carriage 54 includes first wheels 58 configured to engage withrails on frame 22 (FIG. 2) that allow movement of platform assembly 26relative to X-axis 30. Second carriage 56 includes second wheels 60arranged perpendicular to first wheels 58 of first carriage 54. Secondwheels 60 engage with opposing rails 62 of first carriage 54 and allowmovement of platform assembly 26 relative to Y-axis 32. Sewing machine34 (FIG. 1) is seated on a machine platform 64 that couples with secondwheels 60 via carriage supports 66. A support structure 68 is coupled tomachine platform 64. Support structure 68 includes a pair of uprights 70and a framework 72. Stitch regulator 50 is mountable to framework 72.

Housing 52 of stitch regulator 50 includes a first section in the formof an angled facing plate 74 and a second section, or a rear section 76.Angled facing plate 74 includes a first pair of longitudinal edges 75,and rear section 76 includes a second pair of longitudinal edges 77. Ina preferred embodiment, angled facing plate 74 and rear section 76 aremanufactured utilizing an aluminum extrusion process for cost effectivefabrication. Second pair of longitudinal edges 77 forms a snap-fitconnection with first pair of longitudinal edges 75 for ease ofassembly.

Following assembly, housing 52 generally takes the form of a triangularprism. This shape facilitates the fit of stitch regulator 50 withquilting table 20 (FIG. 1), and allows clear visibility of theunderlying head of sewing machine 34 and its needle.

A first handle 78 and a second handle 80 extend from facing plate 74.Keypad controls 82, in the form of a membrane keypad, are mounted onfacing plate 74, and a run switch 84 is mounted on first handle 78. Afirst conductor 86 extends from stitch regulator 50 and couples to amotor control input port, conventionally known as a foot pedalconnection 88 (see FIG. 6) of sewing machine 34 (FIG. 1). Foot pedalconnection 88 is, in turn, in communication with a motor 89 (see FIG.6), of sewing machine 34. A second conductor 90 extends from stitchregulator 50 and is in electrical communication with a first sensor 92coupled to first carriage 54. A third conductor 94 extends from stitchregulator 50 and is in electrical communication with a second sensor 96.

First and second sensors 92 and 96, respectively, may be rotary opticalencoders capable of measuring at least one direction of movement (e.g.X-axis 30, Y-axis 32) of platform assembly 26 and a velocity ofmovement. As such, first sensor 92 is referred to hereinafter as anX-axis rate sensor 92. Similarly, second sensor 96 is referred tohereinafter as a Y-axis rate sensor 96. This direction and velocityinformation can be provided to a microcontroller (discussed below) ofstitch regulator 50 for providing position feedback of platform assembly26, hence sewing machine 34 (FIG. 1).

In general operation, a user selects the operational parameters ofstitch regulator 50 via keypad controls 82. The user can then manuallytranslate platform assembly 26 by holding onto first and/or secondhandles 78 and 80, respectively, to move sewing machine 34 relative tothe underlying fabric held on quilting table 20 (FIG. 1). In anautomatic mode, motor 89 of sewing machine 34 will run in response tothe movement of platform assembly 26, speeding up and slowing down inresponse to movement of platform 26, in order to yield consistentstitches.

FIG. 5 shows a partial front view of stitch regulator 50 illustratingkeypad controls 82. In a preferred embodiment, keypad controls 82 areformed utilizing a rugged, moisture resistant membrane keypad that mayoptionally include tactile and audible feedback. A singleinterconnecting flex cable extending from the membrane keypad caninterconnect with a microcontroller (discussed below) of stitchregulator 50. Stitch regulator 50 further includes a display 98 forpresenting information pertaining to particular operational modesselected by a user through actuation of keypad controls 82.

Keypad controls 82 include a number of user selectable buttons includinga SETUP button 100, an up arrow button 102, a down arrow button 104, aTHREAD CUTTER button 106, a BOBBIN button 108, and a NEEDLE JOG button110. Additional buttons on keypad controls 82 include an AUTO modebutton 112, a MANUAL mode button 114, and an OFF button 116. Thoseskilled in the art will recognize that keypad controls 82 need notinclude all of the described buttons but may alternatively include asubset of the above-described buttons or additional buttons notdescribed herein.

Selection of the various buttons of keypad controls 82 causes thegeneration by stitch regulator 50 of a motor control signal (discussedbelow). The motor control signal is input into sewing machine 34(FIG. 1) via foot pedal connection 88 (FIG. 6) to appropriately drivemotor 89 (FIG. 6) of sewing machine 34. The specific function of each ofthese buttons will be described in connection with the flowchart of FIG.9.

FIG. 6 shows a block diagram of stitch regulator 50 for use with sewingmachine 34 (shown in ghost form). Stitch regulator 50 includes amicrocontroller 118 having parameter inputs that include X-axis ratesensor 92, Y-axis rate sensor 96, keypad controls 82, and run switch 84.Microcontroller 118 has a first output line 119 in communication with atleast one digital potentiometer 120. An output of digital potentiometers120 is in communication with a matrix, or crosspoint, switch 122, andmatrix switch 122 is in communication with a run relay 124. A motorcontrol signal 126 is output from run relay 124 for input at foot pedalconnection 88 via first conductor 86.

Some sewing machines include a thread cut connection 130 that may be aconnector port for a foot control. Through the utilization of a footcontrol, the user can send a thread cut signal to automatically severthreads, rather than through the conventional process of moving a massof fabric to manually cut threads. As an alternative to the conventionalfoot control for thread cutting, microcontroller 118 has a second outputline 132 in communication with a thread cutter relay 134. A thread cutsignal 136 is output from thread cutter relay 134 for input at threadcut connection 130 on sewing machine 34 via a conductor 138.

In addition to the above, microcontroller includes a third output line140 in communication with display 98, and a fourth output line 142 incommunication with a buzzer circuit 144 for optional audible signalingto a user.

In a preferred embodiment, microcontroller 118 is an integrated chipthat contains all the components that make up a controller, such as acentral processing unit (CPU), memory for a stitch regulator operationprocess 146 in the form of executable code, memory for data such as alookup table (LUT) 148, and one or more timers. Microcontroller 118executes stitch regulator operation code 146 in response to inputs from,for example, X-axis rate sensor 92, Y-axis rate sensor 94, keypad 82,and run switch 84, and selectively outputs motor control signal 126,thread cut signal 136, associated text at display 98, and optional audioat buzzer 144.

FIG. 7 shows a block diagram of a portion of the stitch regulator 50. Inparticular, FIG. 7 provides additional details of digital potentiometer120, matrix switch 122, and run relay 124. Stitch regulator 50 isadapted for use with a wide variety of sewing machine types. To thatend, various digital potentiometers 120 are utilized because differentsewing machine types call for very different values for maximum andminimum motor speed. As shown, digital potentiometer 120 includes a onekilo ohm potentiometer 147, a ten kilo ohm potentiometer 149, and afifty kilo ohm potentiometer 150. The specific potentiometers that makeup digital potentiometer 120 in this configuration are not a limitationof the present invention, but can vary in accordance with variousdesigns, motor specifications, potentiometer sensitivities, and thelike.

Matrix switch 122 performs two functions. The first function of matrixswitch 122 is to connect the proper one (or more) of potentiometers 147,149, and 150 with foot pedal connection 88 (FIG. 6) on the differentsewing machines. The second function of matrix switch 122 is to providethe proper motor control signal 126 (FIG. 6) for motor off. Differentmachines call for different control signals for motor off. For example,“machine A” may require an open circuit for motor off, “machine B” mayrequire a short for motor off, and “machine C” may require a particularresistance, such as one hundred forty seven kilo ohms for motor off.

The three terminals (TIP, RING, TERM3) form the electrical interface offirst conductor 86 for foot pedal connection 88 (FIG. 6) at sewingmachine 34 (FIG. 6). Most sewing machines utilize mini audio type twoterminal jacks (ring/tip). However, others use three terminals(tip/ring/term3). This particular jack is not a limitation of thepresent invention. Those skilled in the art will recognize that thepresent invention may be readily adapted to accommodate other types ofconnection ports for other sewing machines.

Run relay 124, when energized, connects foot pedal connection 88 (FIG.6) on sewing machine 34 (FIG. 6) to the correct digital potentiometer120, i.e., potentiometers 147, 149, and 150 through matrix switch 122.When de-energized, run relay 124 connects foot pedal connection 88 to amotor off signal, again through matrix switch 122. Consequently, runrelay 124 is used in normal operation to provide motor control signal126 to turn off motor 89 (FIG. 6) and/or to control its speed. Inaddition, if stitch regulator 50 loses power for any reason, run relay124 will be de-energized, resulting in a motor off signal.

FIG. 8 shows a graph 152 typifying a motor characteristic 154 for sewingmachine 34 (FIG. 6). In this situation, motor characteristic 154represents an actual potentiometer value 156 needed to obtain aparticular motor speed 158. In contrast, an ideal linear relationship160 of motor speed 158 versus potentiometer value 156 is alsoillustrated in graph 152.

It has been discovered that the relationship between a desired motorspeed 158 and a potentiometer value 156 setting is not necessarilylinear for each machine type. Nor is this relationship the same betweenvarious machines. Consequently, in order to adapt stitch regulator 50for use with a variety of sewing machine types, each sewing machine isto be profiled, the results of the profiling being utilized to generatelookup table 148 (FIG. 6).

Profiling is accomplished, for example, by measuring the motor speed(e.g. revolutions per minute) of motor 89 (FIG. 6) as a function ofmotor control resistance. There are several methods for measuring motorspeed. One such method calls for controlling a motor input signal with adigital potentiometer, and measuring the actual motor speed produced bythe motor input signal to generate graph 152. Consequently, lookup table148 (FIG. 6) can be constructed to include an actual potentiometer value156 (i.e., resistance) needed for a particular machine type thatproduces a desired motor speed 158. Alternatively, or in addition,lookup table 148 can be constructed to include a potentiometer valuedifference between the actual potentiometer value 156 needed and theideal potentiometer value typified by ideal linear relationship 160 fora desired motor speed 156.

Profiling can be performed for a multiplicity of machine types, theresults being stored in one or more lookup tables 148, so that stitchregulator 50 can be implemented with a variety of industrial, long arm,and home sewing machines.

FIG. 9 shows a flow chart of stitch regulator operation process 146.Stitch regulator operation process 146 is executable code recorded in amemory element of microcontroller 118.

Stitch regulator operation process 146 begins with a task 162. At task162, stitch regulator 50 (FIG. 2) is initialized. Initialization task162 occurs at system power up of stitch regulator 50. System power upmay occur in response to actuation of a separate power switch (notshown), in response to power up of sewing machine 34 (FIG. 6), or whenone of AUTO mode button 112 (FIG. 5) and MANUAL mode button 114 (FIG. 5)is pressed.

In response to task 162, a query task 166 is performed. At query task166, the system timer is monitored. When there is not a system timeroverflow condition, process 146 loops back to an input of query task 166to monitor for a system timer overflow condition. However, when a systemtimer overflow condition is detected at query task 166, process 146proceeds to a task 168. Consequently, query task 166 causes an overallprocess loop to be initiated. The system timer may be set at fiftymilliseconds. As such, the process loop may run about every fiftymilliseconds, the loop traversing process 146.

At task 168, keypad controls 82 are scanned for keypad entry by a userand debounced. In response to task 168, a series of query tasks may beperformed to determine the nature of any keypad entry and a subsequentaction executed by microcontroller 118 (FIG. 6).

For example, following task 168, a query task 170 is performed. At querytask 170, microcontroller 118 determines whether AUTO mode button 112(FIG. 5) has been selected. When AUTO mode button 112 has been selectedprocess control proceeds to a task 172. At task 172, microcontroller 118determines the velocity of sewing machine 34 (FIG. 1) transported onplatform assembly 26 (FIG. 4).

Following task 172, a task 174 is performed. At task 174,microcontroller calculates motor control signal 126 (FIG. 6) forautomatic operation. In response to calculation task 174, process 146proceeds to a task 176.

Referring to FIG. 10 in connection with tasks 174 and 176 of process146, FIG. 10 shows a table 176 of formulas executed by microcontroller118 for determining motor control signal 126 for input into sewingmachine 34 (FIG. 1).

Table 176 includes a first velocity formula 178 for computing velocityof sewing machine 34 in a first direction, i.e., both directions oftravel along X-axis 30 (FIG. 4), using input from X-axis rate sensor 92(FIG. 6). In addition, table 176 includes a second velocity formula 180for computing velocity of sewing machine 34 in a second direction, i.e.,both directions of travel along Y-axis 32 (FIG. 4), using input fromY-axis rate sensor 96 (FIG. 6). These velocities result from movement,or lack thereof, of sewing machine by a user holding onto first and/orsecond handles 78 and 80, respectively (FIG. 3), and manuallymanipulating sewing machine 34.

Next, the result of first and second velocity formulas are utilized tocompute a magnitude of the velocity of platform assembly 26 and sewingmachine 34, i.e. T(VEL), utilizing a magnitude velocity formula 182. Themagnitude of the velocity, T(VEL), computed using magnitude velocityformula 182 is input into a target motor speed formula 184. Target motorspeed, in revolutions per sec (RPS), is computed as a product of themagnitude of the velocity of platform assembly 26 and a user enteredstitch density, in stitches per inch (SPI).

A digital potentiometer value 156 (FIG. 8) is computed as a function ofthe target motor speed and a potentiometer value, or correction factor,from lookup table 148 (FIG. 6) that relates to the particular motorcharacteristic 154 (FIG. 8) for sewing machine 34. Digital potentiometervalue 156 is computed using a potentiometer value formula 186. Theresulting potentiometer value 156, i.e., WIPER, can then be communicatedfrom microcontroller 118 to digital potentiometers 120 (FIG. 6) togenerate motor control signal 126.

Referring back to process 146 (FIG. 9), in response to the computationtasks 172 and 174, task 176 is performed. At task 176, motor controlsignal 126 is generated. In this iteration of process 146,microcontroller 118 selectively controls potentiometers 120 to setpotentiometers 120 to potentiometer value 156 to generate motor controlsignal 126. This motor control signal 126 is communicated over firstconductor 86 (FIG. 6) to foot pedal connection 88 (FIG. 6) via matrixswitch 122 and the energization of run relay 124 (FIG. 6). Since process146, under the control of the system overflow timer at query task 166 isrepeated approximately every fifty milliseconds, stitch regulator 50 canreadily respond to the movement of sewing machine 34 in AUTO mode toproduce the desired stitch density by variously speeding up or slowingdown motor 89 (FIG. 6) in response to a manually manipulated platformvelocity.

When in the AUTO mode, up and down arrow buttons 102 and 104,respectively (FIG. 6), can be utilized to adjust the desired stitchdensity, i.e., the desired stitches per inch (SPI). Thus, in AUTO mode,the motor speed is set based on the x/y velocity measurement and adesired stitch density.

Referring back to query task 170, when microcontroller 118 determinesthat AUTO mode button 112 has not been selected, process controlproceeds to a query task 190. At query task 190, microcontroller 118determines whether MANUAL mode button 114 (FIG. 5) has been selected.When MANUAL mode button 114 has been selected process control proceedsto a query task 192. At task 192, microcontroller 118 determines whetherrun switch 84 (FIG. 2) is closed. MANUAL mode allows a user to actuatemotor 89 (FIG. 6) by actuating run switch 84.

At task 192, when microcontroller 118 determines that run switch 84 isclosed, process 146 proceeds to a task 194. At task 194, motor controlsignal 126 (FIG. 6) is set to the pre-programmed speed. In the MANUALmode, actuation of up and down arrow buttons 102 and 104, respectively,adjust the pre-programmed manual motor speed. At task 192, whenmicrocontroller 118 determines that run switch 84 is open, i.e., notactuated by the user, process 146 proceeds to a task 196. At task 196,motor control signal 126 (FIG. 6) is set to off in accordance with theparticular sewing machine utilized, as discussed above. Following eitherof tasks 194 and 196, process 146 proceeds to task 176 to generate motorcontrol signal 126 in accordance with the setting determined at eitherof tasks 194 and 196.

Referring back to query task 190, when microcontroller 118 determinesthat MANUAL mode button 114 has not been selected, process controlproceeds to a query task 198. At query task 198, microcontroller 118determines whether OFF button 116 (FIG. 5) has been selected. When OFFbutton 116 has been selected, process control proceeds to a task 200. Attask 200, motor control signal 126 (FIG. 6) is set to off in accordancewith the particular sewing machine utilized, as discussed above.Following task 200, process 146 proceeds to task 176 to generate motorcontrol signal 126.

Referring back to query task 198, when microcontroller 118 determinesthat OFF button 116 has not been selected, process control proceeds to aquery task 202. At query task 202, microcontroller 118 determineswhether SETUP mode button 100 (FIG. 5) has been selected. When SETUPmode button 100 has been selected, process control proceeds to a task204. At task 204, motor control signal 126 (FIG. 6) is set to off inaccordance with the particular sewing machine utilized, as discussedabove. In addition, display 98 (FIG. 2) may be cleared. Following task204, process 146 proceeds to a task 206.

In the SETUP mode, various menus are presented on display 98 (FIG. 2).These menus enable a user to select a machine type and a duration for apower off time out. This machine type is utilized to access lookup table148 (FIG. 6) for potentiometer settings and/or a correction factorrelated to the motor characteristics of the particular sewing machine34. The power off time out is a safety feature that causes stitchregulator 50 to turn itself off after a settable number of minutes ofinactivity. In the SETUP mode, up and down arrow buttons 102 and 104,respectively (FIG. 6), are utilized to adjust the machine type selectionand the power off time out. At task 206, these setup control parametersare saved.

Following task 206, program control proceeds to task 176 to generatemotor control signal in the form of a motor off signal. Of course, itshould be understood that task 206 need not be complete prior togeneration of a motor off signal. Rather, generation of a motor offsignal may be performed in conjunction with task 204.

Referring back to query task 202, when microcontroller 118 determinesthat SETUP mode button 110 has not been selected, process controlproceeds to a query task 208. At query task 208, microcontroller 118determines whether NEEDLE JOG button 110 (FIG. 5) has been selected.When NEEDLE JOG button 110 has been selected, process control proceedsto a task 210. At task 210, motor control signal 126 (FIG. 6) is set toa minimum motor speed value in accordance with the particular sewingmachine utilized. This allows the needle to be raised out of the fabricsurface. In this mode, motor 89 (FIG. 6) runs as long as NEEDLE JOGbutton 110 is held down. In response to task 210, process 146 proceedsto task 176 to generate motor control signal 126 at a minimum motorspeed setting.

Referring back to query task 208, when microcontroller 118 determinesthat NEEDLE JOG button 110 has not been selected, process controlproceeds to a query task 212. At query task 212, microcontroller 118determines whether BOBBIN button 108 (FIG. 5) has been selected. WhenBOBBIN button 108 has been selected, process control proceeds to a task214. At task 214, motor control signal 126 (FIG. 6) is set to a maximummotor speed value in accordance with the particular sewing machineutilized. This allows a bobbin to be wound. In this mode, motor 89 (FIG.6) runs as long as BOBBIN button 108 is held down. In response to task214, process 146 proceeds to task 176 to generate motor control signal126 at a maximum motor speed setting.

Referring back to query task 212, when microcontroller 118 determinesthat BOBBIN button 108 has not been selected, process control proceedsto a query task 218. At query task 218, microcontroller 118 determineswhether THREAD CUTTER button 106 (FIG. 5) has been selected. When THREADCUTTER button 106 has been selected, process control proceeds to a task220. At task 220, motor control signal 126 (FIG. 6) is set to off inaccordance with the particular sewing machine utilized, as discussedabove. In addition, a task 222 is executed. At task 222, microcontroller118 signals thread cutter relay 134 (FIG. 6) to send thread cut signal136 (FIG. 6). In this configuration, thread cut signal 136 is a closureof thread cutter relay 134 causing a short across the thread cutterinputs of sewing machine 34 (FIG. 1) at thread cut connection 130 (FIG.6). Following tasks 220 and 222, process 146 proceeds to task 176 togenerate motor control signal 126 as a motor off signal.

Referring back to query task 218, when microcontroller 118 determinesthat THREAD CUTTER button 106 has not been selected, process controlproceeds to a task 224. At task 224, microcontroller 118 continuesoperation in the current mode in accordance with the last buttonsselected. In response to task 224, process 146 proceeds to task 176 togenerate motor control signal 126 in accordance with the current mode.

A task 226 is performed in connection with task 176. At task 226, themode information is presented on display 98 (FIG. 5). Mode informationmay include, for example, a machine type and power off timeout in SETUPmode, notification of AUTO mode, desired stitch density, and currentmotor velocity when in the AUTO mode, and notification of MANUAL mode,pre-programmed motor speed, and on/off notification when in the MANUALmode. Of course, those skilled in the art will recognize that the textpresented in display 98 can take on a great variation in accordance withthe programmer's preferences for data display.

Following task 226, process 146 loops back to system timer query task166 to monitor for a system timer overflow condition causing anotheroverall process loop to be initiated. Thus, execution of stitchregulator operation process 146 enables a user significant options foroperating sewing machine 34 mounted on a moveable platform, such asplatform assembly 26 (FIG. 4).

In summary, the present invention teaches of a stitch regulator for usewith a sewing machine transported by a moveable platform. The stitchregulator includes a microcontroller that uses velocity signals of themoveable platform, and then uses motor characteristics related to thetype of sewing machine and a desired stitch density to calculate anaccurate motor speed. Thus, the stitch regulator yields consistentstitch regulation across a variety of sewing machine types and across awide variety of motor speeds for a sewing machine. The stitch regulatoris located separate from the sewing machine for ready incorporation witha variety of sewing machines, moveable platforms, and quilting tables.In addition, the keypad controls of the stitch regulator are intuitiveto utilize and the extruded housing, assembly, and membrane keypadresults in a stitch regulator that is durable and cost effectivelymanufactured.

Although the preferred embodiments of the invention have beenillustrated and described in detail, it will be readily apparent tothose skilled in the art that various modifications may be made thereinwithout departing from the spirit of the invention or from the scope ofthe appended claims. For example, the process steps discussed herein cantake on great number of variations and can be performed in a differingorder then that which was presented.

1. A stitch regulator for use with a sewing machine transported by a moveable platform, said sewing machine having a motor control input port, and said stitch regulator comprising: a housing configured to be coupled to one of said sewing machine and said moveable platform; a sensor adapted for communication with said sewing machine for determining movement of said sewing machine on said moveable platform; and a microcontroller contained in said housing and in communication with said sensor, said microcontroller generating a motor control signal in response to said movement of said sewing machine, for input into said motor control input port.
 2. A stitch regulator as claimed in claim 1 further comprising a handle extending from a facing plate of said housing for enabling manual movement of said sewing machine on said moveable platform relative to a piece of fabric.
 3. A stitch regulator as claimed in claim 2 wherein said handle is a first handle, and said stitch regulator further comprises a second handle extending from said facing plate and spaced apart from said first handle.
 4. A stitch regulator as claimed in claim 2 further comprising a run switch mounted on said handle and in electrical communication with said microcontroller, and actuation of said run switch enables provision of said motor control signal.
 5. A stitch regulator as claimed in claim 1 wherein said housing comprises an angled facing plate.
 6. A stitch regulator as claimed in claim 5 further comprising keypad controls mounted on said angled facing plate and in electrical communication with said microcontroller.
 7. A stitch regulator as claimed in claim 1 wherein said housing comprises: a first section having a first pair of longitudinal edges; and a second section having a second pair of longitudinal edges that form a snap-fit connection with said first pair of longitudinal edges.
 8. A stitch regulator as claimed in claim 1 wherein said housing is in the form of a triangular prism.
 9. A stitch regulator as claimed in claim 1 wherein said sensor comprises: a first sensor for determining velocity of said sewing machine in a first direction; and a second sensor for determining said velocity of said sewing machine in a second direction, said second direction being orthogonal to said first direction.
 10. A stitch regulator as claimed in claim 1 wherein said sewing machine includes a motor exhibiting a motor characteristic, and said microcontroller generates said motor control signal in response to said motor characteristic in combination with said movement of said sewing machine.
 11. A stitch regulator as claimed in claim 10 wherein said stitch regulator is usable with a second sewing machine, said second sewing machine includes a second motor exhibiting a second motor characteristic, and said microcontroller generates a second motor control signal in response to said movement of said second sewing machine in combination with said second motor characteristic when said stitch regulator is in use with said second sewing machine.
 12. A stitch regulator as claimed in claim 1 further comprising an input element in communication with said microcontroller, said microcontroller generating said motor control signal in response to a command entered at said input element in combination with said movement of said sewing machine.
 13. A stitch regulator as claimed in claim 12 wherein said command comprises a desired stitch density, and said motor control signal is configured to regulate a speed of a motor of said sewing machine to achieve said desired stitch density.
 14. A stitch regulator as claimed in claim 1 further comprising: an outlet configured for communication with said motor control input port; and at least two potentiometers interposed between said microcontroller and said outlet, said at least two digital potentiometers being selectively controlled by said microcontroller to generate said motor control signal.
 15. A stitch regulator as claimed in claim 1 further comprising: an outlet configured for communication with said motor control input port; and a matrix switch interposed between said microcontroller and said outlet for receiving said motor control signal and directing said motor control signal to an output bus of said matrix switch selected by said microcontroller.
 16. A stitch regulator as claimed in claim 1 wherein said sewing machine includes a thread cut control port, and said stitch regulator further comprises a thread cut control element contained in said housing and controlled by said microcontroller for generating a thread cut signal for input into said thread cut control port.
 17. A stitch regulator for use with a sewing machine transported by a moveable platform, said sewing machine having a motor control input port, and said stitch regulator comprising: a housing configured to be coupled to one of said sewing machine and said moveable platform, said housing having an angled facing plate; a handle extending from said facing plate for enabling manual movement of said sewing machine on said moveable platform relative to a piece of fabric; a sensor adapted for communication with said sewing machine for determining movement of said sewing machine on said moveable platform; a microcontroller contained in said housing and in communication with said sensor; and keypad controls mounted on said angled facing plate and in electrical communication with said microcontroller, said microcontroller generating a motor control signal in response to a command entered at said keypad controls in combination with said movement of said sewing machine for input into said motor control input port.
 18. A stitch regulator as claimed in claim 17 wherein said handle is a first handle, and said stitch regulator further comprises a second handle extending from said facing plate and spaced apart from said first handle.
 19. A stitch regulator as claimed in claim 17 wherein said housing further comprises a body section having a first pair of longitudinal edges that form a snap-fit connection with a second pair of longitudinal edges on said facing plate.
 20. A stitch regulator as claimed in claim 17 wherein said housing is in the form of a triangular prism.
 21. A stitch regulator for use with a sewing machine transported by a moveable platform, said sewing machine including a motor exhibiting a motor characteristic, and a motor control input port in communication with said motor, and said stitch regulator comprising: a housing configured to be coupled to one of said sewing machine and said moveable platform; a sensor adapted for communication with said sewing machine for determining movement of said sewing machine on said moveable platform; a microcontroller contained in said housing and in communication with said sensor; an outlet configured for communication with said motor control input port; and at least two potentiometers interposed between said microcontroller and said outlet, said at least two digital potentiometers being selectively controlled by said microcontroller to generate a motor control signal in response to said motor characteristic in combination with movement of said sewing machine for input into said motor control input port.
 22. A stitch regulator as claimed in claim 21 wherein said stitch regulator is usable with a second sewing machine, said second sewing machine includes a second motor exhibiting a second motor characteristic, and said microcontroller selectively controls said at least two digital potentiometers to generate a second motor control signal in response to said second motor characteristic in combination with movement of said second sewing machine when said stitch regulator is in use with said second sewing machine.
 23. A stitch regulator as claimed in claim 21 further comprising a matrix switch interposed between said at least two potentiometers and said outlet for receiving said motor control signal and directing said motor control signal to an output bus of said matrix switch selected by said microcontroller. 